I. Field of the Invention
This invention relates to a novel method for the preparation of starch sulfate esters. More particularly, the invention relates to a method for the preparation of starch sulfate esters by the reaction of an inorganic fluorosulfate reagent with a starch base under specified reaction conditions.
II. Brief Description of the Prior Art
The modification of starch by chemical derivatization is well known and documented in such sources as "Starch And Its Derivatives," by J. S. Radley (1968) Fourth Edition, published by Chapman and Hall, Ltd. London. More particularly, the prior art teaches the preparation of starch sulfate esters in water by the reaction of organic reagents with starch bases. The methods of the prior art therefore result in the production of organic by-products which are difficult to remove properly from the reaction mixture. Specifically, it is well known to use trimethylamine-sulfur trioxide complex to produce starch sulfate esters. However the by-product, trimethylamine, resulting from the reaction is very difficult to completely remove from the final starch ester.
It is therefore an object of this invention to provide a convenient and economical method for preparing starch sulfate esters. It is also an object of the invention to provide a method for the preparation of starch sulfate esters in water which results in the production of inorganic by-products which may be readily removed. Other objects of the invention will be apparent from the following description.